Evaporator



A1194, 1936., RASAN'DBERG mL 2,049,475-

EVAPORATOR r Fild D ec'. 14, 1934 I Y ZISheets-Sheet l Aug. 4, 1936. R. kA. SANBERG ET Al.

EVAPORATOR Fiied Dec. 14, 1934 2 sheets-*sheet 2 V E D .5

Tay #SW7 er;

Patented Aug. 4, 1936 PATENT oFElcE avsroas'roa l f.

Bay A. Sandberg and Oscar F. Gottlieb, North Chicago, lll., assigner: to Oakes` Products Corporation, North Chicago, lll., a corporation of Michigan Application December 14, 1934, Serial No. 757,441

7Claiml.

This invention relates to a sheet metal evaporator having an individually formed header.

-More specifically this invention relates to an evaporator for refrigerators having sheet metal shells defining a plurality of passageways for refrigerant therebetween and forming the side and bottom walls of a sharp freezing chamber and provided with a separate tubular header secured to the ends of the sheet metal shells.

In the co-pendingapplication of Ray A. Sandberg entitled Evaporator unit and process", Se-v rial No. '736,183 filed July 20, 1934, there is described and claimed a method of making evaporators for refrigerators by placing two metal v sheets in juxtaposition withl a thin brazing shim or sheet therebetween and heating the vsoiormed pack to brazing temperatures for joining the sheets together along all inner contacting surfaces. The sheets are stamped prior to the brazing operation so as to form embossed portions thereon which provide ducts for the refrigerant.

The sheets are also stamped with semi-cylindrical depressions which register with a similarly formed depression'in the other sheet to form a .2 5 tubular header.

We have now found that in some instances it is not desirable to subject the header material to the brazing temperature. We have therefore now provided an evaporator unit in which the 39 header is formed separately from the brazed' together sheets which provide the refrigerant passageways. The sheets are bent into the desired form to conne a sharp freezing chamber and the separately formed header is soldered, brazed 35 or welded to the ends of the sheet. The header A sheet metal evaporatorunits without subjecting 40 the header portion of -said unitsto the temperatures used in securing the sheets together.

Since the header portion generally has a more extended surface which must resist pressures within the evaporator unit than does the brazed 45t/together shell portion we can form the header of thicker gauge metal. than the metal in the shell section. In this manner the pressure resisting strengths of the two portions can be balanced without wasting metal as yas heretofore 50 necessary when the unit was formed in one piece.

It is, therefore, an object of this invention te provide an evaporator for refrigerators having separately formed headers and sheet metal walls 55 deilning a sharp freezing chamber.

l The evaporator of this in-f` vention therefore provides for the production oi' f (Cl. 62-128) v A-further object of this invention is to provide an evaporator unit having a separately formed v header and brazed together shell defining a plurality of passageways therebetween in communication with said header.

A main object of this invention is to provide an evaporator for refrigerators having a header portion formed from relatively thick gauge metal and a brazed together sheet metal shell portion formed from thinner gauge metal and secured l0 to the header in air tight relation whereby the strengths of the two portions can be balanced 'and the evaporator can be prepared from a minimum amount of material without reducing the pressure resisting capacity of the unit.

A specific object of this invention is to provide an evaporator unit for refrigerators composed of separately formed sheet metal shells providing passageways for refrigerant and definingthe sideY and bottom walls of `a sharp freezing chamber 20 and a header securedto the ends of said shell without being subjected to the temperatures used in forming the shell. A l

Other and further objects of this invention will be apparent from the following detailed description of the annexed sheets of drawings whic form a part of this specification.

On the drawings Figure i is a top plan view of an evaporator unit according to this invention. Y

Figure 2 is a front elevational view of the evaporatorunit shown in Figure 1.

Figure 3 is an enlarged cross sectional view taken substantially along the vlines III-III of Fig. 2 with part in elevation.

Figure t is a broken plan view of the outer vsheet metal shell before it is bent to define a sharp freezing chamber and showing in dotted lines the inner shell, as it is positioned against the outer shell. v

Figure 5 is a. cross sectional view taken substantially along the lines V-V of Figure 4.

Figure 6 is a brokenplan view of the embossed sheet of metal forming the inner shell of'the 45 evaporator unit.

As shown on the drawingsv In Figure lathe reference numeral Il indicates generally an evaporator unit composed of a tubular metal header Il and a sheet metal shell portion I2 joined with said header in a manner to be hereinafterA described. The shell portion l2 is formed from an outside sheet .9 shown in Figure 4 and an inside sheet Il shown in Fig- 65 -cated ends I4 of the sheet 9 also register with thev ure 6 which are placed in juxtaposed relation and joined together by the thin brazing shims sandwiched therebetween according to the method described and claimed in the Sandberg co-pending application Serial No. 736,183 above referred to.

The sheet 9 is stamped to form a plurality of parallel semi-cylindrical corrugations I3 extending longitudinally across the sheet. These corrugations I3 provide passageways for the refrigerant as will-be hereinafter described. 'Ihe ends of the sheet 9 are bifurcated as shown at I4 to provide cut away portions between the corrugations I3 for a 'purpose to be hereinafter described.

The inner sheet I5 is stamped to provide thereon a pair of beads I6 and I1 extending transversely of the sheet intermediate the ends and sides thereof. A plurality of oval shaped embossed portions I8, I9, 20 and 2| `are also stamped into the sheet I5 near one side of the sheet.

The ends of the sheet I5 are stamped to provide thereon a plurality of semi-cylindrical corrugations 22. These corrugations 22 extend away from the ends of the sheet only for a short distance as shown in Figure 6. The portions of the sheet between the corrugations 22 are bifurcated as shown at 23. The sheets 9 and I5 are placed in juxtaposed relation as shown in Figure 4 so that the corrugations 22 of the sheet I5 register with the ends of the corrugations I3 of the sheet 9. 'I'lie bifurbifurcated portions 23 of the sheet 6. AAs is more fully described in the `(xo-pending application of Ray A. Sandberg, Serial No. 736,183, thin metal shims composed of a brazing metall are sandwiched between the sheets 9 and I5.

The sheet I5 is preferably formed somewhat wider than the sheet 9 so that its sides may be bent around the sides of the sheet 9 to provide flanges 24 and 25 for holding the sheet together. The so` formed'pack,' with the metal shims therebetween, is then heated between dies to a temperature sufficient to melt the metal shims so that they can fuse into the adjoining surfaces of Vthe sheets 9 and I5 to secure the same together.

The brazed metal 26 so formed (Figure 5) has lleted portionsA 21 at each corrugation I3 and 22. This llet 21 is formed, when the brazing metal melts down, by capillary action of the sheet metals 9 and' I5. The fillets 21 strengthen the so formed together shell and prevent leakage between the corrugated portions of the shell.

The so brazed together shell is then bent into the shape shown in Figure 2 to provide the bottom 28, sides 29 and 30 and sloping top portions 3| and 32 of a sharp freezing compartment 33. The beads I6 and I1 on theinner sheet I5 of the shell portion I2 provide supports for an ice tray 35 shown'in dotted lines in Figure 2. The bottom 29 may sei-veas a support for a second ice t'ray 36;

'Ihe oval shaped embossed portions .I8 and 2I of the sheet I5 form backstops for the ice tray 35 while the embossed portions I9 and 29 form back stops for the ice tray 36. V

'I'he separately formed tubular header II is next secured to the shell portion I2 between the sloping top portions 3| and 32. The tubular header canbe prepared by a stamping or drawing operation and the open end closed by solderingl a cap member thereon to form a closed header compartment, or by folding a sheet stamped lwith The tubular header II shown in Figures 1, 2 and 3 is formed by a drawing operation and has a curved end 31 integral with the tubular side walls and a front cover 38 welded to the tubular side walls toclose the header compartment.

As shown in Figure 3, the header I I is provided with outwardly extending anges suchas 39 deflning circular openings such as 40. The openings 40 are positioned to register with the stamped corrugations I3 and 22 of the sheets 9 and I5. These corrugations together form cylindrical tubes which are adapted to snugly t over the flanges 39 of the header tube II. The

tube II issecurely soldered, brazed or welded to the sheet portion I2 by means of welds 42 formed around the ends of the corrugations I3 and 22. The bifurcated ends I4 and 23 of the sheets 9 and I5 provide openings 4I between each corrugation. These openings 4I facilitate the soldering or welding operation in that they permit more clearance for the manipulation of a soldering or welding tool, and make it possible to extend the Weld 42 entirely around the flange 39.

From the above description it is evident that we have provided an evaporator unit for refrigerators composed of a sheet metal shell portion providing a plurality of passageways for refrigerant and a separately formed header portion secured to the ends of said shell portion. In heretofore known sheet metal evaporator units the header was formed integral with the shell portion andy was necessarily of the samegauge metal as the shell portion. By forming our evaporator in two separate portions, it is possible to form the header from heavier gauge metal than is used in forming the shell portion so that it can withstand higher pressures. It is known that the header metal must be stronger than the metal of the shell portion since the refrigerant ducts in the shell portion are reinforced by the larged brazed areas between each small corrugation. Therefore when the header portion is formed integral with the shell portion, it is necessary to use sheet metal of a thickness sufficient to withstand the pressure in the header. 'I'his thickness is more than is required for the shell portion and since most of the metal is used for forming the shell portion, a large proportion of the metal is wasted. Since the evaporators -of this invention are preferably formed of brass this waste amounts to a considerable item in mass production. Evaporators having separately formed headers and shell portions can readily-be made from two different types of metal. For example the shell portion can be formed of brass while the header can beformed of steel.

Furthermore, in` processes of welding sheet l metal portions together to form the shell portion or expansion chamber of an evaporator unit the sheet metal must necessarily be heated to temperatures suiliclent to cause fusion of the metal itself along the welds. This heating of thesheet metal necessarily weakens the tensile strength of the metal and its resistance to distortion.

' invention, this header portion is not subjected to these high welding temperatures and all ofl its metallurgical characteristics are preserved. The metal forming the header portion can be worked cold thereby retaining its strength and allowing the use of lighter metal than could -be used if the header portion were an integral part of the unit and subjected to the .temperaturesused in Y amavo 3 thepriorart. lo Weelalmusonr 1an y unit for coman A sheuofaheetmtalbenttofom nheandsidemllsofasham ,hens' onsldhelliilll'- rideimgyheads onsaidshlineartlhla'kftopmvide mimica-cycamonihemdsofslshellinimmaedsforann l: A yryzn .ascendieni W Annuncio; lzlomontheenilsnfmezinner` tofonm tubular `een,a'tely 25 tomedtubulnrhelder r :w

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aidnheuhmttoa ,atotheends ofsnid'aaidlheuderhavingaof Il. In a sheet metal evaporator, a tubular header having a plurality of annular anges extending laterally from each side thereof to define a row of spaced circular openings on each side of the header, ay brassvsheet metal shell portion 5 formed from twoembossed brass sheets secured Y together to denne a plurality of expansion ducts for refrigerant, said ducts being tubular-at the ends thereof ,to deilne circular openings adapted to 4snugly ilt over the annular flanges of the 10 header and means for securing the tubular ends of the shell to the header in air tight relation.

5. An evaporator unit for refrigerators com- I prlsing a braaed together sheet metal portion formed from relatively thin gauge sheet metal, said portion providing .a plurality of refrigerant passageways. and a separately formed header portion of thicker gauge metal having openings delined by laterally extending annular anges which are welded to the ends of said sheet metal portion in communication with the passageways therein whereby the pressure resisting capacities of said portions are equalized and the unit is formed from a minimum of material.

. 6. In a sheet metal evaporator, a tubular header formed from heavy gauge sheet brass and having a plurality of annular ilanges extending laterally from each side thereof to denne a row vof spaced circular openings on each side of the tion,

7: An evaporator unit comprising a pair of 40 secured together metal sheets deilning a plurality of parallel passageways for refrigerant slid sheets being bent to denne a sharp freezing chamber and having inwardly extending top portions in space opposed relation, a tubular header inthe space between' said top portions having s along the sides thereof dedned by laterally extending annular flanges forseating in lthe geways defined by the secured together sheets and recessed cuts in the ends'pf said sheets 5o between each of the passageways donned thereby. said sheets being secured to said header around yeach of the-annular nanges thereof.

RAY A. SANDBERG.

OSCAR. F. Y I t :M 

